Rionya and Terror of the Peaks on the battlefield.
Steps
At the beginning of your combat phase, Rionya triggers, creating a number of token copies of Terror the Peaks equal to the number of instants and sorceries you've cast this turn plus one.
The Terror of the Peaks token(s) enter the battlefield, triggering the nontoken Terror of the Peaks once for each token, and each Terror of the Peaks token for each other token created.
Resolve all Terror of the Peaks triggers, dealing 5 damage to any target for each trigger.